/* 头部样式 */
.oj-header 
{
    background-color: white;
    box-shadow: var(--box-shadow);
    padding: 15px 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

.oj-header .container 
{
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo 
{
    font-size: 24px;
    font-weight: bold;
    color: var(--dark-color);
}

.main-nav ul 
{
    display: flex;
    list-style: none;
}

.main-nav li 
{
    margin-left: 20px;
}

.main-nav a 
{
    color: var(--text-color);
    font-weight: 500;
    padding: 5px 0;
    position: relative;
}

.main-nav a.active 
{
    color: var(--primary-color);
}

.main-nav a.active:after 
{
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--primary-color);
}

.user-actions 
{
    display: flex;
    align-items: center;
}

/* 页脚样式 */
.oj-footer 
{
    background-color: white;
    padding: 20px 0;
    margin-top: 40px;
    border-top: 1px solid var(--border-color);
    text-align: center;
    color: var(--text-light);
    font-size: 14px;
}

/* 响应式设计 */
@media (max-width: 768px) 
{
    .oj-header .container 
    {
        flex-direction: column;
        gap: 15px;
    }
    
    .main-nav ul 
    {
        justify-content: center;
    }
}